CO2 lasers are used in several precision laser machining operations, in particular, hole-drilling in various substrate materials. In such an operation, the laser is operated in a pulsed manner, with an output beam of the laser steered by galvanometer mirrors to locations on a substrate where holes are to be drilled.
A problem with all such lasers is that during a warm-up period after the laser is turned on following a quiescent period, the output-beam direction, referred to as “pointing” by practitioners of the art changes progressively. This is due to rising of the temperature of the laser, and the complex mechanical and electrical design and construction of the laser. This pointing-change adversely affects steering of the beam by the galvanometers mirrors, sometimes to a point where hole-drilling cannot be carried out with a required precision.
The laser temperature, and accordingly the beam pointing, stabilizes after a certain time period, for example 5 minutes, making the galvanometer steering reproducible, as long as the laser remains turned on. This stabilization period, however, represents a period of lost production in the hole-drilling operation. There is a need for a design and construction of a CO2 laser which can reduce if not altogether eliminate the pointing-stabilization period.